Wouldn’t it be fairly easy to find this out by direct experimentation? Cut some roses and place them in the road where they’ll have the exposure you describe without also being trampled or run over.

There are still a lot of variables: how young are the roses (how recently opened, how far along the path to wilting on the bush)? dark pavement or light? atmospheric humidity? how much stem? And how wilted is wilted—just limp or completely collapsed, with petals fallen off?